Toy fishing rod?
I take exception to that, the latest versions of modular carbon fibre are anything but. Rigid, strong and the lightest poles on the market.
I use the Bentley brush as supplied by Gardiners, who cares if it only lasts 5 or 6 months?? If I were still trad I'd be spending more than that on replacement rubbers.
At under £20.00 a pop it's peanuts.
For repeat clean work it is a terrific brush.
On heavily soiled work there are better brushes, something like the Ionic brush is good on work of this nature as the bristles are far more floppy and there are far more bristles per square inch, ergo it isn't just the bristle tips that clean the glass, but all of the bristles, therefore you need to scrub less with a brush like this.
Brushes are so subjective - as you have so obviously noted! - The weight of the brush for me is the most important thing, ditto the pole, the more you can reduce the strain on your body the better.
WFP may be safer, but the effects on your body from using a pole day in, day out are cumulative, you may be young, strong and fit, but it makes a great deal of sense to reduce the wear and tear on your body as best you can.
The difference in the weight between a light brush and a heavier brush may not feel much in your hand, just a few grams difference, but at the end of a 30ft pole (whether a light pole or a heavy pole) when you are fully stretched over a big conservatory for instance, then it really makes a difference.
Ian